Severe Weather

 Severe Weather

Severe weather refers to any dangerous meteorological phenomena with the potential to cause damage, serious social disruption, destruction to property or loss of human life.  Below is a list of different types of severe weather w/detailed explanation from the National Severe Storms Laboratory.

WEATHER WARNINGS  are issued by your local NOAA National Weather Service Forecast Office meteorologists who watch the weather 24/7 over a designated area.

WEATHER WATCHES are issued by the NOAA Storm Prediction Center meteorologists who watch the weather 24/7 across the entire U.S. for weather conditions that are favorable for tornadoes.

 

Thunderstorms

A thunderstorm is a rain shower during which you hear thunder. Since thunder comes from lightning, all thunderstorms have lightning.

A Thunderstorm is classified as “severe” when one of the following occurs:

1.  The storm produces hail greater or equal to 1 inch in diameter

2.  The storm produces winds of 58 mile per hour or greater

The image above was taken of on March 18, 2018 and was classified as a severe storm

What is the difference between a Severe Thunderstorm WATCH and a Severe Thunderstorm WARNING?

Severe Thunderstorm WATCH is issued when weather conditions are favorable for severe thunderstorms to develop. 

Severe Thunderstorm WARNING is issued when severe weather has been reported by spotters or indicated by radar.   Warnings mean there is a serious threat to life and property to those in the path of the storm and you should take shelter immediately. 

 

Flooding

Flooding is an overflowing of water onto land that is normally dry. Floods can happen during heavy rains, when ocean waves come on shore, when snow melts too fast, or when dams or levees break. Flooding may happen with only a few inches of water, or it may cover a house to the rooftop. They can occur quickly or over a long period and may last days, weeks, or longer. Floods are the most common and widespread of all weather-related natural disasters.

Flash floods are the most dangerous kind of floods, because they combine the destructive power of a flood with incredible speed and unpredictability. Flash floods occur when excessive water fills normally dry creeks or river beds along with currently flowing creeks and rivers, causing rapid rises of water in a short amount of time. They can happen with little or no warning.

Flooding occurs in every U.S. state and territory, and is a threat experienced anywhere in the world that receives rain. In the U.S. floods kill more people each year than tornadoes, hurricanes or lightning.

The different types of watches, warnings and advisories associated with flooding are:

FLASH FLOOD or FLOOD WATCH:  Flash flooding or flooding is possible within the designated watch area.

FLASH FLOOD or FLOOD WARNING:  Flash flooding or flooding has been reported or is imminent – take necessary precautions at once! Get to higher ground!

URBAN and SMALL STREAM ADVISORY:  Flooding of small streams, streets and low-lying areas, such as railroad underpasses and urban storm drains is occurring.

FLASH FLOOD or FLOOD STATEMENT:  Follow-up information regarding a flash flood/flood event.

 

Tornadoes

A tornado is a narrow, violently rotating column of air that extends from the base of a thunderstorm to the ground. Because wind is invisible, it is hard to see a tornado unless it forms a condensation funnel made up of water droplets, dust and debris. About 1,200 tornadoes hit the U.S. yearly. Tornado season usually refers to the time of year the U.S. sees the most tornadoes. The peak “tornado season” for the Southern Plains is during May into early June. On the Gulf coast, it is earlier during the spring. In the northern plains and upper Midwest, tornado season is in June or July. But, remember, tornadoes can happen at any time of year. Tornadoes can also happen at any time of day or night, but most tornadoes occur between 4–9 p.m.

What is the difference between a Tornado WATCH and a Tornado WARNING?

A Tornado WATCH is issued when weather conditions are favorable for tornado to develop 

A Tornado WARNING is issued when a tornado has been reported by spotters or is imminent based on radar.   Warnings mean there is a serious threat to life and property to those in the path of the storm and you should take shelter immediately.

 

Lightning

Lightning is a giant spark of electricity in the atmosphere between clouds, the air, or the ground. In the early stages of development, air acts as an insulator between the positive and negative charges in the cloud and between the cloud and the ground. When the opposite charges builds up enough, this insulating capacity of the air breaks down and there is a rapid discharge of electricity that we know as lightning. The flash of lightning temporarily equalizes the charged regions in the atmosphere until the opposite charges build up again.

Lightning causes thunder! Energy from a lightning channel heats the air to around 18,000 degrees Fahrenheit. Lightning is estimated to be approximately 53,540 degrees Fahrenheit (about 5 times hotter than the surface of the sun). This causes the air to rapidly expand, creating a sound wave known as thunder. The stepped leader causes the initial tearing sound, and the ground streamer causes the sharp click or crack heard at a very close range, just before the main crash of thunder.

For more on lightning and lightning safety, click here ——> All About Lightning and/or Lightning Safety

 

 Hail

Hail is a form of precipitation that occurs when updrafts in thunderstorms carry raindrops upward into extremely cold areas of the atmosphere where they freeze into balls of ice. Hail can damage aircraft, homes and cars, and can be deadly to livestock and people.

Hailstones grow by colliding with supercooled water drops. Supercooled water will freeze on contact with ice crystals, frozen raindrops, dust or some other nuclei. Thunderstorms that have a strong updraft keep lifting the hailstones up to the top of the cloud where they encounter more supercooled water and continue to grow. The hail falls when the thunderstorm’s updraft can no longer support the weight of the ice or the updraft weakens. The stronger the updraft the larger the hailstone can grow.

 

Hailstones can have layers like an onion if they travel up and down in an updraft, or they can have few or no layers if they are “balanced” in an updraft. One can tell how many times a hailstone traveled to the top of the storm by counting the layers. Hailstones can begin to melt and then re-freeze together – forming large and very irregularly shaped hail.

Hail size is estimated by comparing it to a known object. Most hail storms are made up of a mix of sizes, and only the very largest hail stones pose serious risk to people caught in the open.

Pea =1/4 inch diameter

Marble/mothball = 1/2 inch diameter

Dime/Penny = 3/4 inch diameter

Nickel = 7/8 inch

Quarter = 1 inch — hail quarter size or larger is considered severe

Ping-Pong Ball = 1 1/2 inch

Golf Ball = 1 3/4 inches

Tennis Ball = 2 1/2 inches

Baseball = 2 3/4 inches

Tea cup = 3 inches

Grapefruit = 4 inches

Softball = 4 1/2 inches

 

 Damaging Winds

Damaging winds are often called “straight-line” winds to differentiate the damage they cause from tornado damage. Strong thunderstorm winds can come from a number of different processes. Most thunderstorm winds that cause damage at the ground are a result of outflow generated by a thunderstorm downdraft. Damaging winds are classified as those exceeding 50-60 mph.

 

 Winter Weather/Blizzards

The term “blizzard” is often tossed around when big winter storms blow in. But the National Weather service has an official definition of blizzard: A blizzard is a storm with “considerable falling or blowing snow” and winds in excess of 35 mph and visibilities of less than 1/4 mile for at least 3 hours.